And there was a glimmer of good news for Minogue - doctors say the breast cancer does not appear to have spread to other parts of her body.
"My heartfelt thanks to the incredible number of people who have sent messages of love and support over the last two days," Minogue said in a statement. "I want to reassure you that I am being well taken care of."
In a brief statement, Minogue's manager Terry Blamey said the 36-year-old is being treated in her hometown of Melbourne.
"Kylie is currently undergoing tests at a first class medical facility in Melbourne in preparation for an operation this week by one of Australia's leading surgeons," Blamey said. "Thankfully tests so far have confirmed the earlier diagnosis that the cancer appears to be confined to the breast."
Minogue shocked the world of show business on Tuesday when she announced she had cancer and was postponing her Showgirl tour dates in Australia and an appearance at Britain's Glastonbury Festival.
She has not been spotted since the announcement, despite news crews and photographers huddling close to her family's home in Melbourne, the city where she rose to fame in Australian soap opera "Neighbours."
Her boyfriend, French actor Olivier Martinez, is with Minogue, she said, and there are widespread reports that her sister Dannii Minogue is flying to Australia to be with her.
"Olivier is by my side and I have a lot of family and friends around me," Minogue said in her statement, which also carried a message of support for other breast cancer sufferers.
"I would also like to extend my best wishes to all of the other women around Australia and around the world who are dealing with the same illness," Minogue said.
This is not the first time the singer has been involved in the fight against cancer. After her father was diagnosed with prostate cancer, Minogue worked to raise public awareness of the disease, and on another occasion, she donated one of her bras to be auctioned off to raise money for breast cancer research.
Minogue launched her singing career with hits such as "I Should Be So Lucky" and "Better the Devil You Know."
Her popularity soared along with her critically acclaimed 2001 hit "Fever" sold 3 million copies and reached No. 1 in charts around the world. Other highpoints for Minogue fans have included "Slow," which was nominated for a Grammy, as well a series of raunchy videos released with singles such as "Can't Get You Out of My Head."